Waters Prep Series Installation And Maintenance Manual page 145

7. Gently press the pump head assembly into place. Apply even pressure to
the front of the head.
Caution:
plunger.
8. Replace the hex-head screws on both pump heads. With a 5/32-inch hex
wrench, tighten them evenly by alternately tightening one then the
other by half turns.
9. Start the pump and set the flow rate to 3.0 mL/min.
10. Be sure the indicator rod moves freely.
11. Push solvent through the two pump heads with a syringe. Solvent
should exit the second pump head. This primes the plunger wash, and
ensures the plunger is lubricated when you start the pump.
12. Reconnect the solvent lines, start the pump, and check for leaks.
Replacing the pump plunger
This procedure requires moderate strength and dexterity as well as a
Tip:
special plunger insertion tool. Contact your Waters Service Representative
before performing it.
The plunger may experience excessive wear if you do not use the plunger
wash. If your pump has been running for some time without the plunger
wash, replace the wash seals (see
page 3-65).
If the plunger sustains excessive wear despite use of the plunger wash system,
rub it with a fine pumice to remove any coating. Then clean it thoroughly to
remove all traces of the abrasive. Replace the plunger seal, and install new
wash and high pressure seals. If this does not extend plunger life, replace the
plunger.
To replace the pump plunger:
1. Remove the pump head and head support assembly.
2. Set the flow rate to 3.0 ml/min. Run the pump unit until the plunger
fully extends, then shut the pump down.
Do not exert any side forces or you could damage the
"Replacing the plunger wash seal" on
Maintenance procedures 3-61